// 清除浮动
.clearfix::after{
  content: ' ';
  display: block;
  overflow: hidden;
  height: 0;
  clear: both;
}
//三角形
@mixin triangle($width,$color){
  width: 0px;
  height: 0px;
  border-top: $width solid $color;
  border-left: $width solid transparent;
  border-right: $width solid transparent;
  border-bottom: $width solid transparent;
}

@mixin mask($cornerleft:4%,$cornertop:4%,$weight:1px) {
    background: linear-gradient(to bottom,#43f1f8 $cornerleft,transparent $cornerleft, transparent (100%-$cornerleft), #43f1f8 (100%-$cornerleft)) 0 0 no-repeat,
                linear-gradient(to top,#43f1f8 $cornerleft,transparent $cornerleft, transparent (100%-$cornerleft), #43f1f8 (100%-$cornerleft)) 100% 100% no-repeat,
                linear-gradient(to right,#43f1f8 $cornertop,transparent $cornertop, transparent (100%-$cornertop), #43f1f8 (100%-$cornertop)) 0 0 no-repeat,
                linear-gradient(to left,#43f1f8 $cornertop,transparent $cornertop, transparent (100%-$cornertop), #43f1f8 (100%-$cornertop)) 100% 100% no-repeat;
    background-size: $weight 100%,
                     $weight 100%,
                     100% $weight,
                     100% $weight;
    border-radius: 0px;
}
